


Don't Leave Me Behind

by BlueViper129



Category: Assassination Classroom
Genre: Blood and Violence, Broken Nagisa, F/M, Major Character Injury, Nagisa is sanely insane, The Author Has OCPD, Time Travel
Language: English
Status: In-Progress
Published: 2020-11-08
Updated: 2021-01-18
Packaged: 2021-03-09 06:07:23
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 4
Words: 19,368
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27459955
Author URL: https://archiveofourown.org/users/BlueViper129/pseuds/BlueViper129
Summary: Going through hell, he decides to travel back in time, to the year when the root of all problems starts.Inspired by: AmareScribere with the story's name "Retrouvailles." The main idea is time-traveling, but apparently, this story will be much different from the mentioned one.I do not own the story nor the characters of Assassination Classroom. All of those belong to Yusei Matsui.
Relationships: Akabane Karma & Shiota Nagisa, Akabane Karma/Okuda Manami, Class 3-E & Shiota Nagisa, Kayano Kaede & Shiota Nagisa, Kayano Kaede/Shiota Nagisa, Shiota Nagisa & Shiota Nagisa, Shiota Nagisa/Yukimura Akari
Comments: 13
Kudos: 34





	1. Prologue - Reset Time

**Author's Note:**

> Hope you guys enjoy the story!

In the dark, standing under the heavy rain, a blue-hair man, whom if the truth was not told, everyone would call him a 16-year-old teenage boy because of his height and his young face, has his face down, looking at the ground. Two streams of water are running on his cheeks. They are not from the rain but actually his tears. He can feel it, even someone standing five meters away from him can still distinguish between the two. 

In front of him, two particular serpentine-shape stones lay on the ground. They are the gravestones of someone, someone that he dearly loves forever in his life. He would do anything he could to protect them. He can even give up his life without hesitation for the sake of their lives. 

But what is in front of him is showing the opposite. He could not protect them, and now they are leaving him behind forever. He feels that he is useless. It is the feeling that he has not had for a long time since he was in that class, the class where his life has changed forever. It was the place where his great teacher had made his life which he used to wander in the dark shining again, where he himself found out the true purposes of his life, and most importantly where he found his true love. 

And now, the images of his love dying in front of him and him unable to do anything to protect her, to save her keep going back. What had happened 10 years ago and yesterday's incident are now eating his mind. “AWWWWWWW.” He lets out a scream while his hands are pulling his wet hair, completely ignoring the surroundings. He still cannot accept the truth, the sight that is laying in front of him.

After an hour standing soullessly under the rain, the 25-year-old man decides to move closer to the two gravestones, knees down, and wraps his two arms around the two stones. He remembers the last moment the three of them being together. It was just yesterday, just like every normal happy day between them. 

_It was a fateful afternoon. In a hospital, a young female figure, not too high, with long brown hair around her waist and amber-pupil eyes hidden behind black sunglasses wearing a yellow dress just came out from the doctor’s office. She definitely was in her disguise so that no one would recognize her. Everyone else in the hospital could see her belly is big enough to tell for sure that she was pregnant._

_Outside the office, sitting on a long chair meant specifically for people who were waiting was a young man with blue hair and blue-pupil eyes. He was very nervous waiting for the girl and her results._

_“Hey anata, why are you looking so worried?” The girl was now in front of the young man whose mind was clearly somewhere else._

_“Huh, ah Akari.” He got himself back to reality and quickly jumped towards the girl who was having a piece of paper in her hands. “So how was the check? Are you and Naoki fine? Is there anything abnormal?”_

_“We’re fine, Nagisa. Don’t be so nervous like that.” Akari smiled at him, feeling delighted that he was worried about her and their son. She gave him the paper in her hands. It was the report of her pregnancy check._

_“You already knew that I’m very nervous and so worried because it’s my first time that I become a father.” Nagisa replied while scratching the back of his head, feeling a little bit awkward. He then looked at the report and nodded at the result. “But I’m glad that both of you are fine.”_

_“I know and I’m really happy about it.” She answered and gave her beloved husband a quick hug. When she released her hug, she took a small picture of black and white out of her handbag. “But anyway, here is another picture of our son, if you really want to see it.” She was waving the picture in front of him, more like teasing him._

_“Yes, of course.” Nagisa who clearly did not care about the tease then quickly took the picture from her hands and had a smile, a happy one, while looking at it._

_Akari slightly laughed at the scene of her childish husband. Then she grabbed his right arm and leaned her head on his right shoulder, feeling the warmth from her husband. “I love you, anata.”_

_Nagisa turned his eyes on his wife and smiled at her. “I love you too.” He then kissed her forehead. “I promise I’ll protect both you and our son. You two after all are my dear family.”_

And now here he is, in the graveyard. “Shiota Akari” and “Shiota Naoki” are the two names engraved on the two serpentine-shape stones. He feels like the world is playing with him. He spends the rest of the night being there with the two gravestones.

\------------------------------

For the next whole week, he completely isolates himself from the rest of the world. He locks himself in the apartment where he and his wife have spent the last four years living together. 

Even the members of class 3E, including his best friend Karma, do not want to bother him during this tough time. They actually want to be there with him, to share the loss together, but they know that he is the one who suffers the most and that the deep wound will not go away anytime soon. 

The last time they saw him was when the whole class was in the hospital, waiting for some miracles to happen. When the doctor stepped out of the operation room and told them that both the girl and the kid could not be saved anymore, they were all filled with sadness. But more importantly, they could see that Nagisa just became lifeless. That is the reason why they decide to give him some time to adjust his life on his own.

The school where he is working keeps contacting him, but there has been no response from him. Since the news of the death of the famous actress Haruna Mase is now all over the place, his students try to find a way to keep in touch with him because they have learned that she is their teacher’s wife, but they still have not heard a word from him.

During the whole week, he still blames his uselessness that caused her death. He really wants her to be with him right now. He has even thought about the idea of going to her side. But then he remembers back to that moment. 

_“I’m sorry, Nagisa. I’m sorry for leaving you behind like this. If possible, find yourself a new girl that you can be with forever, not like me.”_

_“NO AKARI. You are and will always be the only one that I love. Please don’t leave me behind.” He grabbed her red right hand that had been covered with her blood with both of his hands. They kept shaking heavily. Tears from his blue eyes kept running down, landing on their hands._

_Akari felt an endless warmth coming from his words. Looking at him being worried so much, she could not stop blaming herself to be in a state like this._

_“Promise me one thing, Nagisa.” She then looked at him intensely._

_“No, no, no. Please stop talking nonsense, Akari. You’re going to be alright. PLEASE don’t be like this.” He shook his heads, trying to deny what would happen to her._

_“Promise me that you will not follow us by any means. I want you to continue your life, to pursue your goal further. If you follow me now, Naoki and I in the other world will never forgive you.”_

_She then raised her other hand and put it on his cheek. “I love you Nagisa.” Then, her hand suddenly fell from his cheek and landed on the ground._

Every time he has this scene coming back to his mind, he just cannot hold himself together.

Thinking about it, he will not be allowed to go there, at least for now. If that is the case, then the only other option is that he will have to bring her back to him. He figures that there is only one way to have her come back to life. He needs to fix the root of the problems, the year when all of these began. 

Without any other thoughts, he quickly takes with him the picture taken of him and Akari standing in front of the church on their wedding day and also the latest picture of his son that he got from Akari on that eventful day. The top of the picture is now completely covered by dark dried substance that used to be red liquid. It was Akari’s blood. A few of his tears are dropping on the picture. He quickly wipes his eyes and puts the two pictures into his wallet. 

What he has on his body is very casual clothes, his wallet, his wedding ring on his ring finger, and a necklace with another ring hanging on it. It is the wedding ring belonging to Akari. He takes all the most important things with him and leaves everything behind. He leaves the apartment, knowing that he will never come back to this place again.

\------------------------------

In front of him now is the “Horibe” mechanical-electrical store run by his old classmate Itona. He then enters the building with the mindset of doing the thing as quickly as he can.

“Hey Itona.” He greets his old classmate with an unemotional expression.

“Oh. Hi Nagisa.” Itona is shot by surprises. He does not expect at all that Nagisa will be here. It is because he believes that if Nagisa ever gets himself out of his isolation, the other classmates who are closer to him, like Karma and Sugino, will be the first ones to know and they will inform the whole class later. But obviously, he has not received any news from the class. He knows that this only means something will happen. In any case, Itona quickly gets back to his normal state. “I hope you’re still doing well.” 

The blue-hair does not give any response to him, just simply gives a nod and then gets his phone out of his pocket. “Ritsu, are you here?”

“I’m here, Nagisa-kun.” Ritsu then appears on the screen of his phone. The purple-hair girl shows a mixed emotion of relief and sadness. She is relieved that Nagisa has decided to get outside of his prison cell, but she is sad because she has already had a glimpse of what the man wants to do. “Is there something that I can help you with?” 

“Yes. Actually, I need the help of you two. I need you guys to build a time machine for me. Is it possible?”

Itona is again hit by shock with his eyes widening. He is unable to process what just happened. He wonders whether the man is still sane. Even if he is, he really wants to know what he is going to do with the time machine. For the AI girl, she has a sorrowful face displaying on the screen because she knows that her prediction is correct.

“I’m not sure about that.” Itona is the first one to respond after quickly regaining his composure. 

“Well, it may be possible.” Ritsu adds.

“Really?” Itona wants to make sure that what he just heard from Ritsu is the truth.

“Yes, it is. I've traveled over the world to get all different kinds of research data, just in case they will be needed one day. Amazingly to your curiosity, there have been a lot of research facilities that have spent years studying time machines, though nobody has been able to make one.” 

She stops for a moment to see the reaction of her old classmates. Nothing really happens, except that their eyes are now intensely focusing on the screen, waiting for her next explanation. Seeing that, she continues. “However, I can gather all of the information, reorganize all the related theories and data, and finally give some adjustments to those original blueprints to make the final product functional.”

“In short, it is possible to make one, am I correct?” Nagisa acts like he ignores everything else and only focuses on the final result.

“Yes.”

“Ok, then can you print out the final blueprint of the functional time machine?”

“I can, but give me about a day to do all the adjustments.”

“Good. And Itona, can I ask you to build the time machine based on the final blueprint when Ritsu finishes with her work?”

“I guess I can if I have enough materials. However, it still depends on how complicated it may turn out to be.”

“Ok, that’s good enough. I’ll help you with whatever I can.” Nagisa stops for a moment before he continues. “However, I want to make one thing clear before we get started working. You guys better not inform other people about this whole ordeal, especially the class, or else you do not really want to know what I will do.” He looks at them with a smile and his shining blue eyes filled with bloodlust.

Both Itona and Ritsu listened to him, and they’re afraid. One part is that his bloodlust is still immense as usual, but this time, they find out that it is even denser than before. It feels like he has been holding it back for a long time, and this long time is actually only a week since the day she left him. It means that he has been living through hell for the entire week.

But the other reason that is more concerned is the true meaning of what he just said. They know that he will never hurt his friends. He definitely will not hurt them, but it does not mean that he will not hurt himself. They believe that he cannot think straight right now, so they do not know what to do except nodding at the blue-hair man, agreeing to what he proposed.

“It’s nice that both of you can easily understand what I may try to do. Anyway, let’s get to work.” He says to the two while still remaining that smile on his face.

\------------------------------

After three days of working restlessly, they have finished building a time machine. During those three days, “Horibe” store has been closed to prevent any unnecessary interruption from the outsiders.

Now in front of them is the time machine in the shape of a sphere with glass covering the outside. The three who are in the secret room have different expressions at the scene. Itona has still not believed in himself that they were able to build an actual time machine. Ritsu still has her sadness on her face because of the blue-hair man’s reckless actions. For Nagisa, he does not even care about the fact that they just built a time machine. He is unimpressed, but more importantly, he is pleased that he can finally continue with his plan.

After a few minutes of silence, Ritsu decides to bring the most important fact about time-traveling that she has been holding back. “Let me make an important thing about this. There will be a catch with time-traveling…”

“I don’t care.” Nagisa quickly stops her before she says anything else.

“No, even if you don’t care about yourself anymore, I, no, we as a class deeply care about you. So you have to listen to what I'm about to say.” Ritsu completely ignores his words and continues with her words. “The catch is that [???].”

Itona who stands on the side is now horrified by every word coming out from Ritsu. “Nagisa, I think you should stop doing with whatever you’re having in your mind right now. It’s not worth it. The risk is too high.” Itona tries to convince him. “Even Kayano-san will not allow you to do this.” He does not want to mention her in front of him, but if it is to bring Nagisa back to reality, he will do it.

Nagisa’s eyes widen when he hears her name. After a few seconds of thinking, he opens his mouth. “Yeah, you’re right, Itona. I’ve been too unreasonable.”

“Oh, that’s a reli…” Before he has a chance to finish his words, he is suddenly hit on his neck by something from behind, causing him to immediately collapse on the floor. He sees Nagisa’s brown shoes in front of his eyes before being unconscious.

It was Nagisa who chopped Itona’s neck with his hand. Nagisa hit him when Itona lowered his guard because of his “fake” words.

“Itona, I’m sorry, but I don’t have any other choice. It’s either I’m continuing with my plan or I’ll die in madness.” His eyes are filled with sorrows while saying in an apologizing tone.

Ritsu is shocked at what happened in front of her eyes. She wants to do something, but she simply cannot because of her immobility. “Nagisa, you’re better than this. Have you forgotten Koro-sensei’s book of advice? Never let your past control your life. Your present and future are much more important. So please stop your foolish act now. You still have a bright future, Nagisa.”

“Ritsu, you just don’t have any idea when someone whom you dearly love, someone who is destined to be with you until the end of life just dies in front of your eyes.” Nagisa says while looking down at his hands that are now shaking heavily as he remembers the sight of them being covered in Akari’s blood.

Ritsu just becomes dead-silent at his words. It is true that she has gained more and more emotions for the last decade. However, she still cannot truly understand what true love is. It is much more complicated than the basic emotions she has learned before. 

Then he looks back at the screen. “So, that’s it. It’s a goodbye here then. I really appreciate your help in the past few days.”

“You know that there will be no coming back when you start it, right?”

“I just don’t care anymore. At least by doing this, I can be more relieved if I’m to see her again in the other world.” He just simply smiles at what he just said. 

Then, he steps into the time machine and sets up the exact time that he wants to arrive in order to have his plan work. Before he starts the machine, he turns his eyes to his phone and says his last few words to his AI friend. 

“If it happens that you have to tell the other guys about this, make sure they will never follow me. It is my last request and also my last thank to you as a friend. You have been working your way to becoming as humane as you can, and so far, you have been doing a pretty good job. I wish you to continue pursuing your goal further.” 

He puts on a genuine smile at her. “Sayounara.” Then he turns off his phone and pushes the start button. The glass sphere just disappears from the world without leaving behind any traces.


	2. Settling Time

**Notes for the Chapter:**

> AN: Hello everyone! Here is the new chapter, a long one I would say. It was supposed to be updated last weekend, but stuff happened. So, I couldn't have it finish in time. For anyone who reads the other story of mine, I'm sorry to say that there will be a late update for that one (definitely not on Thanksgiving).
> 
> Anyway, hope you enjoy this chapter! Again, more important AN is at the end!

When he opens his eyes, he quickly checks if there is any significant change happening to him. At least for now, he does not see or feel any differences. Although he has not grown significantly regarding his height, which is only 3 centimeters for the past ten years, he can feel that those 3 centimeters do not go away. 

Looking at his surroundings, it seems that he is in a dark alley, and apparently, it is night outside right now. He slowly gets out of the glass sphere and looks at the sky. The moon is in a crescent shape, and it has not been crumbling. Seeing that, he clenches his two hands into fists firmly but also shakingly. It means that he has traveled back to some point during the Assassination Classroom, and he does not want to travel back to this point in time at all.

He wanted to travel back to the time before the moon exploded. He wanted to save his sister-in-law. Although it was not a long time, she was still his teacher, and more importantly, her death was the cause that made Akari suffer the pain of losing somebody she loved and the pain of those tentacles.

_ In a corner of a dark bedroom with light-blue walls was Nagisa and Akari lying on their bed. They were both in their slumbers. At the same time, there was a heavy thunderstorm happening outside, which was predicted to last until morning. Then, a sudden loud thunder caused Akari to immediately get herself up from her sleep. Sitting on the bed, she hugged herself, shaking heavily, with tears running down her cheeks. Whatever was in her dream made her very panicked. This caused Nagisa to quickly wake up. _

_ “Akari, what’s wrong? Is it…?”  _

_ She simply gave him a nod with her tearing eyes. _

_ Nagisa actually knew what had happened. It was Akari’s nightmare, the one that kept reminding her about her sister’s death, the worst thing that she could remember about her sister.  _

_ When Nagisa saw her like this for the first time back when they just started dating, it made him very worried. He just did not know what was going on with her. Not wanting to make him worried too much, she decided to tell him the truth. It used to happen a lot during the time when she still had the tentacles. But she reassured him, saying that it started getting better when he was with her.  _

_ Despite her saying that she was better, every time she went through it, he felt hurt because he could not do anything to ease the pain inside her. _

_ Back to the current moment, seeing her like that, he decided to move closer to her and let her head rest on his chest. She covered her face with his chest and hugged him firmly while still sobbing. He gently patted her head to calm her down. _

_ “Ok, just let it all out. You’ll feel better that way.” He did not know what would be the best course of action to help her except letting her slowly unload her burden. “You must know that I’m always here with you.” He wanted her to share that burden with him. _

_ It took her more than 5 minutes to get back to her usual self.  _

_ She tried to wipe her tears, but Nagisa was the faster one to act. He used his hands to gently remove her tears while smiling at her. “You know, I don’t like to see you in this state at all.” _

_ “I’m sorry. I just couldn’t help it. Sometimes the memory just keeps going back and I still can’t fully accept it.” She was still sniffing after her crying. “But I’m very happy that I still have you with me.” She said while still hugging Nagisa. _

_ He laid a soft kiss on her wet cheek. “So, are you feeling any better now?” _

_ “Yes, thank you so much for being here with me, Nagisa.” _

_ He smiled at the girl. “Do you want to stay at home tomorrow? I can call your manager to delay the play.” _

_ “No, you don’t have to worry that much.” She then released her hug and smiled back at him. “See. I’m totally fine. And with that being said, I’m definitely not going to stay at home tomorrow.” _

_ “Ok, then quickly get back to sleep. You’ll need all the energy you can get for tomorrow.”  _

“I’m sorry, Akari. I couldn’t make it. I couldn’t save your sister. I failed you again.” Although it is not his fault to only get to this point in time, he keeps blaming his uselessness, tears running down his cheeks. 

He wipes his tears and tries to get back to his calm state. He needs to know the exact date so that he can make some proper adjustments to his plan. He takes out his phone to check the date, but it still shows the date in the future. He then concludes that the machine is only a means to transport in space and time without causing any other physical changes, for example, him still being like him in the future and his phone still having the same date before he left.

Then, he works towards the nearby garbage container with the hope that he can find some old, but not too old, newspaper. When he opens the container, the first thing laying right on the top is a very new newspaper, which means that this newspaper was just printed this morning. He looks at the newspaper to see that the date is May 12, 2015. His face does not show any happiness or sadness. 

_ “Nagisa, this time machine can only get you to a time within the interval of 5 years from now. It doesn’t have enough fuels to travel to a time that is past the mark.” Ritsu told him when he and Itona were in the final step of finishing the time machine.  _

_ The 5 years was the number that Ritsu calculated based on the model that they were building, assuming that Nagisa would choose to have a full round trip. In other words, the time machine would get him to, at maximum, 5 years to the past, or the future, and still just have enough fuel to get back to the present—that would be if he did manage to get back. _

However, he already used the time machine to travel back 10 years, meaning that he cannot use the time machine again because it is already out of fuel. The type of fuel it uses is unique. It can be produced only by future Ritsu. Even if he asks Ritsu in this current time period, this Ritsu still cannot make it because of her undeveloped state compared to what she is in the future. 

And even if he managed to find the fuels for the machine, he still could not travel back to the exact timeline that he wanted because of “the catch” that Ritsu mentioned to him at the very end. Therefore, he has no other choice but to accept to go on with his plan in this timeline. This is why he blames himself that he could not save Akari’s sister.

One thing that he did not care to notice is that the fact he got to this point in time is a miracle. With that amount of fuel in the time machine, he, at best based on theoretical calculations, could only travel back to September 2015. With that being said, the chance that he could get back to the point to save Yukimura-sensei is practically zero. 

With all of those out of his mind, the last thing he needs to do now is to dispose of the time machine. Although it cannot function without fuel, it still can cause a lot of trouble if someone is able to find it. The reason they made it mostly from glass is that he forced them to. It is much easier to break the glass than hard steel or any other metal materials. According to his plan, he did intend to destroy it later when he successfully got back in time so that no one would ever try to use it and mess up his work. 

He looks around to find something that he can use to destroy the cover of the machine. Fortunately, there is a long steel pipe lying beside the garbage container. He grabs the pipe and hits the machine. After a minute or two, the sphere machine is now scattered into pieces, small broken glass being over the place. The only thing left is the platinum platform and its engine. It takes him more than twenty minutes to hit them, making sure that they are not working anymore. After that, he buries them deep down in the garbage container along with the pipe. “That should do the job.” And with that, he leaves the alley.

He takes a quick look at the area, and to his surprise, he knows this neighborhood because it is in the same direction that he used to, in the future, walk from his home to his workplace.

Next, he has to find a place to live. However, the only place that he has in his mind now is the apartment that he just left three days ago. “Isn’t it too ironic, Akari?” Maybe he is too attached to the place that he just cannot think of any other good places. Then, he decides to walk to the place where the apartment will reside 10 years later.

\------------------------------ 

In front of him now is a five-story building. It was not a long walk as it only took him 10 minutes to get here. “It has been 10 years, and it hasn’t changed at all.” He says while looking at the building. At first, he was not even sure that the building would be here during this point in time.

Focusing on the target, he makes his steps into the building and walks towards the reception counter which happens to be in a separate room with only a certain space made from glass for communication and a hole big enough for exchanging documentations. Behind the counter, a young woman in her late twenties with long blonde hair seems to be the one who is in charge here.

“Hello Miss, I want to rent an apartment here.” Nagisa goes straight to the point.

“Um, sure. Can I see your ID or any personal document to verify your information?”

“This is my ID, miss.” He says as he takes his in-the-future ID out of his wallet and gives it to her.

He expected this would happen, but it was nothing that he should be nervous about. He knew that there would be no Shiota Nagisa nor anyone with Shiota as last name living around this area. Apparently, this is what he learned in the future. In fact, his past self is now at least 20 minutes driving from here, and he himself knows that his past counterpart would never come to this area during his teenage years.

“Hum, do you have confirmations from your parents?” She asks him after she finishes scanning his ID. She is giving him a concerning look.

Obviously, his ID shows that he is now only 14 years old. Based on his appearance, no one would have any doubt about that. Never in his life that he would appreciate his small figure as at this moment.

“Sorry, but I’m an orphanage. Both of my parents died in an accident not long ago. I don’t have any family left.” He says with a face somehow showing his sincere sadness. It was not a complete lie. After all, he did lose his family.

“Oh, I’m so sorry about that.”

“No, you don’t need to. That’s not your fault.” He returns with a genuine smile on his face. “And if you’re worried about how I’m going to pay the rent, I have enough money for that. So please rest assured.”

“If you say so. Then, Shiota-san…” 

“Hold on a minute. I want to make one thing clear. From now on, please refer to me as Shuwari Naoki. I have my own reasons for that.”

Thinking that he changes his name because he does not want to recall the pain of his parents’ death, the lady decides not to ask any further. “So, Shuwari-san…” 

“Call me Naoki.” Nagisa wants to commemorate his unborn son.

“So, Naoki-kun, would you please sign this document? By signing this, you will agree to the policies, terms, and conditions of this building.” She gives him the document full of words and a pen. 

He quickly scans through the document and immediately signs, using his true name. There is nothing much to the document because this and the one in the future are pretty similar, except that the price this time is twice cheaper than the one in the future. That actually makes sense to him because of the inflation rate. With the money that he is having in his wallet right now, he can pay for four months. Besides that, he can finally confirm from the document that the date is indeed May 12, 2015. 

“Here’s the key to your apartment.” The lady gives him the key with the number 202 from the counter after getting the document back from him.

However, he does not immediately take the key. “Miss, is apartment number 305 currently empty?” Apparently, that was the one that he just left three days ago.

“Let me see…” The lady takes a look at the list of numbers before answering him. “It’s actually empty right now. You want that one?”

“Yes, please.” 

“Ok, here’s the key to 305. Do you know the way?”

“Thanks, and yes, I can figure it out myself.” 

“Then, I wish you a good night, Naoki-kun.”

“Thanks for your help, Miss…”

“It’s Furukawa Yoshiko.”

“Thanks for your help, Furukawa-san. And a good night to you too.” Then he turns his back and gets himself to the elevator. 

‘ _ What a weird kid he is _ .’ That is the lady’s last thought about the man before he quickly disappears from her sight.

\------------------------------

Standing in front of the apartment, he is a little bit hesitant to open the door. After calming himself down for a minute or two, he decides to enter the apartment. He quickly turns around to look at the apartment. “So it has been like this since the beginning, huh?” He feels like all the things that he has been doing for the last three days were nothing because of the familiar atmosphere of the place giving to him.

Right after that, he immediately collapses on the floor in the living room and passes out. It is because the exhaustion from the last three days has caught up to him.

When he wakes up, he realizes that it is already noon. “Well, it seems that I just overslept.” He just says that to the emptiness of the space. 

Ignoring the fact that he is still lying on the floor, he begins sinking in thoughts, going over his plan again. ‘ _ For my plan to work, I have to be somewhere near the class for most of the time without raising any suspicions. _ ’ 

Either he enrolls as a student or he becomes a teacher. In any case, he is confident with his acting skills. Living with a famous actress does let him learn more about acting. However, he needs to carefully consider which option is better.

With his appearance, no one will have doubt that he is a teenager who is still going through his puberty. However, he still needs some source of income for his living. And the most important thing is that he must not let his old classmates be too close to him, especially Koro-sensei’s curiosity of wanting to know more about his students, which can lead to his identity being exposed. 

That leaves him with the only other option, which is to become a teacher of class 3E. If that is the case, he will first need to think of a way to win his old classmate’s trust. 

It is not that he is unconfident in his way of teaching. In fact, within the first two years of teaching, he has already earned the reward of “Teacher of the year.” With his “weird” method of teaching, he was able to get the delinquents in class 3-5 back to the right track, and he was then widely known by the whole school. Many students in other classes really wanted to be taught by him. Seeing him as a nice and cute person, some of the girl students in the school even sent love letters to him, and on Valentine’s Day, he even got chocolate from them. Because of that, he usually got scolded by Akari.  _ “Mo, Nagisa, don’t they really know that you’re already married?” _

However, this is not the case for class 3E. His teaching method is mainly inspired by Koro-sensei. To use the same one on them is to disrespect Koro-sensei and also raise suspicions in them, especially Koro-sensei. Running all the possible ideas that he can think of, he concludes that the best way to do this is to teach them with all he has and let fate determine the flow of his plan. If they accept him, then that is good. If not, then he has to think of another way, but that will be something of the future. “Let just hope for the best.” 

After going over the first step of the plan, he quickly takes out his phone and fills in an application on Kunugigaoka Junior High School’s website. Obviously, from now on, he will go with the name Shuwari Naoki. He needs to make sure that his true identity will only be known by the receptionist lady. 

He is a little bit impressed that the school board instantly messages him back after he uploaded his files. His interview is scheduled to be tomorrow morning.

All that aside, he now needs to buy some stuff for his “long survival” and prepare for tomorrow's interview. It is a very important interview because it will decide whether his plan will be processed forward or not. He decides to go to the closest convenience store to get some daily supplies and a cheap cap to cover his blue hair. Then, he makes his way to the mall to get some casual clothes, a cheap plain suit or two for his work, some hair dyes and contact lenses for his later disguise. 

After he goes back to his apartment, he quickly unloads the goods and goes to the bathroom with the dyes and lenses that he just bought. Standing in front of the mirror, he looks at himself one last time before changing his appearance.

_ It was a sunny Sunday. Both Nagisa and Akari felt very exhausted from their works of the week, so they decided to spend their day-off together at home. She was sitting on the couch in the living room while he was lying on the same couch with his head on her lap. He was closing his eyes, enjoying their little moment being together. _

_ “Nagisa.” _

_ “Yes, Akari?” He opened his eyes to look at her. _

_ “You know, your hair is so soft and comfortable. Sometimes it makes me feel jealous.” She said while happily playing with his short blue hair.  _

_ “Hum, is that so?” _

_ “Yeah, but that’s why I really love your hair.” _

_ “So you only love my hair but not me?” He tried to put sadness on his face in the most convincing way as he could. _

_ “You should know that you always act like a spoiled kid when you’re with me.” She just sighed at her childish husband.  _

_ “Then spoil me.” The sadness on his face was completely replaced by his genuine smile. _

_ “Ok, you asked for it.” Her hands then let go of his hair, moved down to his abdomen, and massaged around the area. When she saw that he really enjoyed what she was doing, she suddenly stopped, smirking at him.  _

_ Nagisa felt that something weird was about to happen and decided to move away from her. However, it was too late. She already had him down on the couch and started tickling him nonstop. _

_ “S-s-stop it, Akari. I-I can’t take it anymore.” After a minute or two, she decided to stop. He was panting heavily while she was laughing out loud. _

_ “But you know, we’re here now like this all thanks to your beautiful hair.” She told him after they got back to their normal states. _

_ “You’re right.” He nodded at her comment. He remembered back to the day they first met. It was thanks to her during that moment that he found something inside him glowing. Looking back at the present, he felt very delighted to be with her for the rest of his life.  _

_ “However…” This time, seeing that she just let her guard down, he immediately locked her down on the couch, smirking at the girl. “It’s payback time.” _

\------------------------------

Standing in front of the gate of the main campus of Kunugigaoka Junior High School is a figure with below-average height, brown hair and brown-pupil eyes, wearing a plain gray suit. His name is Shuwari Naoki. 

It has been a while since the last time he was here. In fact, it was about 6 months ago, in the future, when class 3E had a reunion on the satellite campus.

And right now, his face is not showing any emotion, but deep inside, his feelings are mixed. 

He is glad that he can see Koro-sensei again and spend more time with him. He even thinks of trying to save him at the end as another extra bullet point in his plan. 

But most importantly, he can see Akari again. It is not that he is going to do any things as he did with Akari when they were dating in the future, but the sight of her still alive is enough for him to continue with the things he is doing. Right now, the relationship between them can only be teacher-student, that is if he becomes a teacher of class 3E. 

And then he feels bad that he cannot be himself. He has to deceive all of them.

“Hey you there.” An unfamiliar voice disrupts his thoughts. He turns around to see a man in a security uniform running towards him. “Why are you still here? Classes have already started. And why are you not in your school uniform?” 

“I’m sorry, sir, but I’m not a student. I’m actually here for my job interview.”

“Really?! My bad. I thought, you know…” The security guard is surprised to learn that the boy in front of him is older than he thought. “Anyhow, if that’s the case, let me show you the way to the Human Resources office.”

“Thank you very much.”

He decides to follow the security man to the mentioned office. Along the way, he notices that the hall is completely empty. This makes sense to him because his appointment is 9 AM and everyone must be in their class by now. 

When he arrives at the office, he is greeted by a faculty there and asked for some of his personal information to verify the application. He is then instructed to go to the top floor for the interview with the Principal. In this school’s system, all the teachers can only be approved and hired by the Principal himself. Nagisa, or now known as Naoki, takes no surprise at this as he knows about the Principal’s ideals.

There are a lot of unknown variables that can mess up his whole plan at any time, and Principal Asano is one of them. Nagisa knows about the Principal’s educational philosophy and his reasons behind it. However, to say that he truly understands what is in the Principal’s mind is to be oversighted. In fact, to Nagisa, the Principal is completely unpredictable. The best he can do is to make the Principal not to focus on him too much. 

Other variables to his plan are the members of class 3E. And the most tricky one is still no other than Koro-sensei himself. Koro-sensei is like a ticking bomb in his plan, preparing to blow up the plan at any moment.

Upon arriving at the Principal’s office, he calms himself down before opening the door.

“Good morning. I guess you must be Mr. Shuwari.”

Principal Asano is sitting on his chair across the room, far away from the door. Nagisa decides to move closer to the man to have a better conversation. 

“Yes, I’m Shuwari Naoki. Good morning to you, Mr. Principal.” He greets the man in his dark red suit while giving him a slight bow. Looking around at the room, he notices something very weird. ‘ _ Is this big room always dark and empty like this? _ ’

“I think you know that our school only hires people who know their stuff deeply well. So, I want to make sure of one thing first. Do you believe that you’re capable of teaching here?”

“It’s not that I’m exaggerating things but I’m very confident in my ability to teach.” Nagisa remains unfaded before the tense atmosphere the Principal is giving off. It is just the same as what Nagisa sensed from him when they met each other for the first time in the 3E campus before that hellish midterm. 

“Then you don’t mind taking some tests first so that we can see how good your knowledge is before continuing with other things?”

“If that is what you require, then I have no right to reject it. After all, I really want this job.”

After that little exchange, Nagisa is then instructed to a room where he takes his tests. There are five tests, covering the five main subjects: Math, Japanese, English, Science, and Social Studies. All the questions in the tests are at the last-year college level. However, to Nagisa, answering these questions is like him taking his breath. He learns new things every day so that he can help with whatever his students want to know. That is how dedicated he is to teaching. 

After about two and a half hours, he finishes the tests and gives them back to the main office. All the tests are graded by the Principal himself. After waiting for ten minutes in the same room, he is called back to Principal Asano’s office.

“I’m very satisfied with the results you gave me.” Principal Asano says to him while looking at the results he is having in his hands. Nagisa only lost one point out of a total of 500 points. 

“Starting tomorrow, you’ll be class 2C’s homeroom teacher. You’ll be responsible for all the subjects of that class.” The Principal intended to have the guy in charge of class 3C. However, he is just a new teacher, so he may not know about the school system. Therefore, he wants to know more about the guy’s teaching method, the one that he said he is so confident in, before getting him to higher classes. 

“From what I know, there is a special class on the mountain of this school. And if I’m correct, the class is specifically for the misfits. With that being said, I want to be a teacher in that class.”

Principal Asano is just hit by surprises, raising an eyebrow at Nagisa’s words. The Principal feels something off about the guy. “If you’ve already known about that class, then can you tell me what is the most appropriate reason that I would send a talent like you to teach on that campus?” He asks the guy with his usual cold voice. The Principal admits that the guy has some talents, so he definitely wants him to be on the main campus.

“Because I want to challenge myself.” 

The conversation between the two just becomes tenser and tenser. Even so, both of them still remain calm. 

“You should give me a more convincing reason than just that.”

Nagisa is silent for a minute or two to think of the best reason. He runs all the possible answers in his mind. Unfortunately, nothing will work except the final trump card he has on his sleeves. “I heard rumors about a certain yellow tentacle creature lingering around the school campus.” 

He does not want to use it at all. It is bad to have the Principal focus on him, but it will be much worse if he is not allowed to teach in class 3E. If the cost is only to raise some suspicions in the Principal, then he will accept it. He can deal with those things later on. 

“What do you mean?” The Principal suddenly becomes dark. His mood is now completely changed.

“What I’m trying to say is that I already knew the real truth hidden in the campus on the mountain. And for that, I think you should let me teach that class. Is it enough to be the best reason for you, Mr. Principal?”

“So you’re trying to blackmail me?” The Principal narrows his eyes at the guy.

“In some way, I guess. You don’t want to have this to be exposed to the public, do you?” Nagisa calmly replies while carefully observing the Principal’s reactions. “But all I ask from you is to let me teach in that class. Isn’t it too good of a deal?”

“Tell me, what is your true purpose for coming here?” 

“I’ve already told you many times, I want to be a teacher in that class. That’s all I want and need from you.” 

The room becomes dead-silent for the next minute. The two men only exchange gazes at each other. While Nagisa is still wondering whether his trump card actually works or not, Principal Asano is the one who breaks the silence first.

“Shuwari-sensei, you’re allowed to teach in class 3E, starting tomorrow.” The Principal says while tightening his hands together. 

“It’s good to hear you saying that.” Nagisa feels relieved when he hears that. However, he does not show that outside. To show any emotion right now is to lose the whole battle. 

“However, you will have a meeting with someone right after this to discuss your work in more detail.”

“Thank you for your consideration. Then, I’ll take my leave now.” He turns around and walks towards the door. He suddenly stops at the door. “And you don’t have to worry about it. I promise you that as long as you allow me to teach in that class, I’ll never disclose the secret.”

Principal Asano’s eyes are fixed on Nagisa until he steps out of the room without looking back at him. ‘ _ Shuwari Naoki. What do you really want? You’d better not do any harmful things to this school. _ ’ Principal Asano has to admit that this is the first time that someone is able to force him to take a defensive move in order to protect his ideals. ‘ _ I think I have to spend some time learning more about this guy. _ ’

Nagisa is then sent to a room that is much fancier than the room where he took the tests. The room seems to be designed to receive special guests. He sits down on one of the two couches, facing each other, in the middle of the room. He is waiting for a specific person. Nagisa himself can easily deduce who the person will be, based on the flow of the current situation.

“Hi, you must be Shuwari-sensei. I heard about you from the Principal earlier.” Stepping into the room is a man with black spiky hair wearing a black suit. Following him is a lady with brown pony-tail hair also in a black suit. They walk towards Nagisa and sit on the opposite couch, now facing him. “Allow me to introduce myself. I’m Karasuma from the Ministry of Defense. And this is my underlining, Otani.”

“It’s a pleasure to meet both of you. I’m Shuwari Naoki, but please call me Naoki.” 

“Then, Naoki-sensei, let’s get straight to the main point.” Karasuma looks straight into Nagisa’s eyes while lowering his tone, showing his seriousness. “About the thing that you said earlier in the Principal’s office, is it true that you want to teach in class 3E?”

“That is true. I really want to be a teacher in that class.” Nagisa shows his determination through his cold tone. “And before you even ask, I know what is truly hidden in that campus. The presence of two members of the Ministry of Defense here is alone to confirm my words.”

Right now, Karasuma cannot sense any danger given off from the man, but everything that the Principal just told him makes him feel uneasy. Besides, the man’s sharpness and observation skills are really something. All of those things make Karasuma very cautious of the man’s presence. “If you’ve already known, then am I right to assume that you’re an assassin?”

“Well, of course not.” Nagisa tries to ease the awkward atmosphere in the room. “I’m just a normal person who is dedicated to learning more about the world, and that is to include some mysterious creatures.” He answers the agents with a smile. “But it doesn’t change the fact that I do really enjoy teaching.”

Karasuma just shivers as the man smiles at him. He feels that something very peculiar is behind that smile. It is like the man is trying to hide his killing intent, or bloodlust he would say. During the entire conversation, he always has his guard against the guy. There is still something troubling him. ‘ _ He said he enjoys teaching, but is that really his sole purpose? _ ’

Noticing that Karamusa-sensei is deeply in thoughts, Nagisa decides to continue to prevent him from thinking too much about the situation. “So I’ve already told you what you need to know. Is there something else that you wish to ask? Or is it that you don’t want me to be there at all?” 

“To be honest, there’s nothing I can do at this moment. Even though I don’t want any strangers to interfere with the current situation, the Principal has already accepted the request. We’re here just to make sure that you’re not going to expose the secret to the public.”

“You don’t have to worry about that. I’m not going to tell anyone about the secret.”

“I hope you keep your promise. And one more thing you should know is that I’m the PE teacher in class 3E, so for most of the school time, I’ll be on the campus. So don’t try to do anything funny.” Karasuma reminds him with his once-again serious tone.

“Well, that makes us colleagues. Then, Karasuma-sensei, I hope you will take care of me, starting from tomorrow.” Nagisa stands up from the couch and walks away from the two agents. “I’m really looking forward to our final school year.” He turns around to give both the agents a farewell before leaving the room.

Arriving at his apartment, he quickly jumps into his first work of preparation, which is to prepare his lesson plans for class 3E and how he should deal with Koro-sensei’s curiosity. 

**Notes for the Chapter:**

> AN: After you finish reading this chapter, you might say that I'm being too detailed when it comes to describing things. But I think all of those, even some small details, are very important for the characters' development, especially Nagisa in this case. But maybe, I'm just having a severe OCPD :))). I do want to have a decent chapter before publishing it.
> 
> The whole point of time traveling will be revealed more in later chapters, actually the next one (a change in pace as you will see). I try to make it as logical as it can be.
> 
> For anyone hoping for Aguri being saved in this story, I'm sorry to say that I can't. I have my reasons for that (well it's related to the plot of the whole story anyway).
> 
> And this time, I won't set any specific deadline for the next chapter. I have my final exams in about 2 weeks. If possible, I may be able to have one chapter updated for each story before the exams. After finals, I will spend the whole break dedicated to the two stories.


	3. Interlude 1 - Disturbing Time

**Notes for the Chapter:**

> Hello everyone! Here is the next chapter, a new pace added to the story.
> 
> Hope you enjoy this one! As usual, more AN is at the end.

Back to the present time, which is 10 years after the end of Assassination Classroom, right after Nagisa disappears from the world, Ritsu quickly sends a message to all her old classmates about the situation. She needs someone to check whether Itona is still fine after getting the hit from Nagisa. It seems to her that it was a pretty strong hit. “I’m sorry, Itona. I couldn’t do much to help you.”

“Message to Class 3E from Ritsu: EMERGENCY. All the class members, please quickly come to Itona’s store now. I’ll explain the details when you guys get there.”

\------------------------------ 

“Um, Karma, do you want something to drink?” A purple-hair female figure in her mid-twenties, wearing her casual clothes and glasses, standing in the kitchen, loudly asks the red-hair man who is lying on the couch in the living room.

“Well, a cup of hot tea would be nice right now.” The mentioned man answers with his voice loud enough so that the girl can hear.

“Ok, just hang on a minute.”

“Thanks, Manami.”

Karma and Manami have been married for about 5 months. In fact, they were the first two in class 3E to start dating when they were still in their first year of college. However, they were one of the last couples to marry. It was because after graduation, their work was so much that they had to keep pushing their wedding back.

The first married couple was Nagisa and Kaede which happened to be 2 years ago. Although the other 3E members expected them to be together eventually, they were surprised to know that they were the first couple in the class to marry. 

And the list went on with Chiba and Rinka being the next married couple, then Maehara and Hinata, Isogai and Megu, and Sugino and Yukiko being a month before the marriage of Karma and Manami. 

And now, Karma, lying on the couch with his hands under his head, is looking at the ceiling in deep thoughts. He is thinking back to all the events that just happened this week. He, as well as everyone else in class 3E, has to take in so many things in the past week that are way too overwhelming for him and the others to be accepted as the truth. But one undeniable fact he knows for sure is that at this very moment, no one in the class suffers more than Nagisa. 

And as Nagisa’s best friend, Karma is blaming himself for not being able to help him get through this dark time. ‘ _ Damn it, I’m just a total loser after all, just letting my best friend be like that and doing nothing to help him. What a good friend you are, Karma. _ ’ He grinds his teeth at the thought.

Unnoticing to him, Manami just comes back from the kitchen with her hands each holding a cup of hot tea. Seeing her husband like that, she feels heartbroken because she knows what he is thinking. She does not want him to constantly blame himself for his uselessness. It is not the Karma that she knows and loves. ‘ _ It’s not you at all. You don’t have to do this yourself, Karma. _ ’ She thinks to herself while shakingly holding the two cups.

And one thing comes to her mind. ‘ _ But then, do I even have the rights to say those things when I’m just in the same situation as him? _ ’ The sadness is now clearly shown on her face. She is almost at her limit, still trying her best to hold her tears inward. ‘ _ Kaede, please tell me. Tell me how to overcome this situation. _ ’

For the past week, she has been trying to be as normal and calm on the outside as possible. But deep inside her, the grief just keeps growing. At some points, those negative feelings took over her and she was broken down. When she found herself alone, she just let out her sadness to the empty space.

Fortunately, she completely finished the Artificial Blood Project about a month ago. With that being said, she decided to have a temporary break from her work by spending more time at home being a normal housewife and improving her love life with Karma before returning to the field. It was by this time that the eventful incident hit her and everyone else in class 3E. If she were to work on some projects during this dark time, she would not be able to keep her mind straight to do her work properly. 

Leaving those thoughts aside, she tries to calm herself down with each step closer to her husband. Without making any noise, she gently puts the two cups down on the table and silently sits on the wing chair next to the couch.

“Karma?” She weakly raises her voice, calling her husband.

“Huh? Oh, Manami.” Karma is called back to reality, changing his gaze from the ceiling to his wife. “I was just lost in some random thoughts that I didn’t even notice you. Sorry about that.” 

Karma gets up and has himself sit on the couch. “Thanks for the tea.” He smiles at his wife. He then picks up the cup and blows on the hot tea, acting like nothing happened. 

However, Manami knows that it was a fake smile, no true happiness laying behind that smile. She decides to just give him a nod in return and then keeps her head down looking at her cup of tea. 

This quickly gets Karma’s attention. He then puts his cup down and looks at Manami.

“What’s wrong, Manami? Are you not feeling well?” Karma asks with a worrying face.

She was a bit hesitant before answering. “You know Karma, when I first learned about Kaede’s death, I was very depressed and I still am at this moment. She was my best friend. It…it hurts me a lot that I still can’t believe it as the truth.” She lets out her tears wetting her shirt.

“…” Karma silently observes her, but deep inside, a part of him is very happy because this is the first time since the incident that Manami decides to be honest about her feelings. ‘ _ Of course I know how you’ve felt for the past week. _ ’ He already knew about that but he decided to ignore it because he wanted to give her some personal time to adjust it. He did not want to forcefully make her feel happy all of a sudden because after all, it was a serious matter. 

But then, the other part of him does not want to see her in this miserable state. What Manami does not know is that every time she thought she was alone and let out her sadness, he was always there, standing on the other side of the door, hearing her scream. ‘ _ I’m not an idiot, Manami. _ ’ With every tear and scream she let out, he could feel an enormous pain tearing his body apart. 

And now, he listens to her words while firmly clenching his hands into fists.

“I’m saying all of this because…because I know that you’re still blaming yourself for not doing much to help ease down the situation. I can relate to that because I am too.” Manami says while still sobbing and squeezing her hands together tightly on her lap. “But this isn’t you, Karma.” She looks at him with tears running down her cheeks. “Not only does it hurt you, it also makes me feel more painful to see you like that. At least, you should be yourself so that…so that I can have a place to lean on.” She comes to hug him with her head into his chest. “You’ve already done your best, so please, please…stop blaming yourself.”

Karma is frozen by her sudden actions. ‘ _ She saw through me once again. _ ’ He then returns the hug by gently grabbing his arms around her. 

“I’m so sorry, Manami.” He lowers his head to her ears and whispers to her with a regretful face. “It was just something that I thought I could have been more useful, something that I thought I could have made the situation better than what it is right now. I didn’t know that it would also hurt you.”

After he finishes his words, he can feel she just tightens her hug.

“Can you please promise me that you will never be like that again?”

“Manami…”

“Promise me.”

“I promise…” He also tightens his hug in return. “I promise I’ll never be like that again, and from now on, I’ll be the place for you to lean on whenever you want.”

“Hum.” She gives a nod, showing her satisfaction with his answer. However, she still does not want to release the hug right now. “Karma, can we stay like this a little bit longer?” Manami shyly asks him. “It’s just that we’ve not been together much like this since the incident.”

“Of course. It’s not just you. I also want to be close with my little wicked witch too.” 

They affectionately smile at each other.

And they stay like that for about 5 minutes before Manami slowly loosens her hug. Sensing the motion from Manami, he also releases the hug so that she can get herself up. She quickly uses her hand to wipe out any leftover tears on her cheeks. Then, she returns to her seat on the wing chair while Karma still sits on the couch. 

“You’re feeling better?”

“Um.” She nods and smiles at him. “Thanks Karma.” Then she again looks down at her cup of tea while still remaining her beaming smile. “You know, at some point, we have to let go of the past and move forward with our future. Isn’t that what Koro-sensei taught us?”

“You’re right. I was just too short-sighted. I wasn’t in my straight mind at all. Again sorry about that.” Karma sighs before he continues. “But I still want to do something useful. At least, I want to help Nagisa deal with his problem, but I really don’t know the best way to do it.”

“How about you go and have some words with him?”

“Well, I did think about that, but then I’m not really good at talking down to people. I mean I’m not a psychologist, and I’m definitely not Koro-sensei.”

“Just be yourself, Karma.” Manami says while giving him a warming smile. “What Nagisa needs to know is that there are people who still deeply care about him. You’re his best friend and you care about him. That’s all that matters.” 

“You really think so?”

Manami nods and then reaches out to hold his hand firmly. “Karma, you don’t have to take all the burden to yourself. You still have me and the class, right? You can ask Sugino to go with you if you’re still unsure. He’s also Nagisa’s best friend.”

“Thanks Manami. I think I’ll do that.” Karma happily smiles back at his wife. “Honestly, I don’t know what would happen if you weren’t here with me.” He says while also holding her hands back. “But I have to say, that was very brave of you, Manami. I’m very happy to see you’re also being honest with your feelings.”

“Well, I’ll take that as a compliment. Thanks.” She shyly looks away from him for a moment. 

Then, she remembers one thing that she has been wanting to ask him for a while. “So Karma, are you sure you’re not getting any trouble about you staying home right now? I mean, I’m really happy to see you take a break from your work once in a while and spend more time with me, but I don’t want it’s because of me that will get you into unnecessary troubles.”

“Nah, it’s fine. You don’t have to worry about that. I already talked to my boss about the requests and he kindly accepted.”

Karma has already got himself a very good position in the Ministry of Economics, Trade and Investment because of his talents in leadership and his intelligence. Before the incident, Karma used to work every day, even the weekends, dealing with piles of piles of documents, mostly relating to the new economic reform in order to get everything back to normal from the recent worldwide crisis. But then things happened and he decided to take a two-week break from work. He also requested his boss to work only on the weekdays after his break. Because of his hard work since the first day and his accomplishments in the past 3 years, his boss unhesitantly accepted his requests. 

The reason he made those requests was that he wanted to spend more time with Manami. He even thought about doing this a long time ago, but work and responsibilities did not allow him to do so. Then, the incident struck, and it gave him enough force to break the barrier. It was because he saw Nagisa’s state after the incident that made him realize that life is full of unexpecting things and that he may lose someone he loves at the time he least expects. With that being said, he has to value every second of being with Manami.

“But I’m more worried about you, Manami. As things are right now, I don’t think you should be back to your work at any time soon. You better stay at home for a little longer.”

“I guess that will be the case. I don’t think I can do much in this state of mind, so I’ll extend my break a bit longer. Though, I still need to recover quickly because the next patch of interns may wait for me. I can’t let them down.”

“Alright, just remember not to push yourself too hard, ok?”

“Um, I know.” Manami happily nods in return.

Suddenly, both of their phones ring at the same time. They quickly take out their phones to check the message.

“Ritsu?” Manami asks shockingly. It is because she has not heard a word from her AI friend since her wedding.

“You’re also getting Ritsu’s message?” Karma is surprised to know that both of them receive Ritsu’s message. “I have a feeling that something bad is about to happen.”

\------------------------------

About twenty minutes after the message was sent to the class members, they have all arrived in front of Itona’s store with only confusion shown on their faces. All the class members are present except Nagisa and Itona. 

“So that runt still locks himself up? It’s so pathetic for a guy like him to be like that.” Terasaka says to the class.

“Hey Terasaka, isn’t it a little bit rude to say something like that?” Hara says while giving him an annoying glare.

“Something wrong with what I said? Everyone here is feeling the same. We all feel bad for Kaede. It’s not just him you know.”

“But Kaede means much more to him than us. You should know it, Terasaka.” Kimura points his finger at Terasaka after he finishes his words.

“Yes, we all lost Kaede and we feel bad about that. But for Nagisa, he lost more than that. He lost two, Terasaka. TWO.” Hinata also angrily responds to Terasaka. 

“Fine, fine, my fault. But he better gets himself out of there as soon as possible before I have to forcefully ask some guys from the Housing Department to demolish the building that he’s in right now.”

“Don’t worry about that.” Everyone turns to the source of the voice. “I decided to have some words with him tomorrow. I can’t just let the guy be like that forever. With that being said, is there anyone else who wants to join? Sugino, you’re in?” Karma then turns to look at Sugino.

“Of course. I also thought about it a moment ago. I’m glad you brought that up, Karma.” Sugino says with a smirking face. “I mean, we are his best friends. So I’m willing to do anything to help him get back to his normal self. Well, if needed, I’ll even smack him in the head with my bat to hit his stubbornness out.”

“Right, I’ll bring some mustard and wasabi just in case.” Karma says with a Koro-sensei’s face. 

Everyone just sweatdrops after his comments, except for Manami. She happily smiles at her husband because she is glad to see him being himself again. ‘ _ That’s the Karma that I know, though I do hope that you won’t actually go overboard with it. _ ’

“Tomo-kun, you were just kidding about the last part, right?” Yukiko says with a smile on her face. This causes Sugino to shiver.

“Um, Yukiko, you see, I was just joking.” Sugino nervously waves his hands at Yukiko. “I didn’t mean it at all. Well, not at all. Ahhh, what I meant is that I want to help Nagisa. That’s it. Nothing more.”

“Ok, I know you two just want to ease down the tenseness, but please remember not to make things go out of control.” Isogai says to Karma and Sugino but then remains his eyes on Karma. “Especially you, Karma. I’m not sure Nagisa is in the mood for any of your pranks.”

“Ok, ok, I know what I’m doing, so don’t sweat about it.” Karma tries to calm down the class. “Anyway, is there anyone else wanting to join us?”

“I believe Karma and Sugino should be good enough since you two are his best friends and I don’t think we should overwhelm Nagisa with twenty-plus people flooding into his place all of a sudden.” Megu gives out her opinion.

“I agree.” All the other class members say in unison.

“Ok, let’s just go with that then. Hope you two do your best job in talking down to Nagisa.” Isogai concludes the matter and the two mentioned guys nod at each other, showing their determination in fixing this situation.

“Leaving that matter aside, the most important thing right now is why we are all here.” Isogai leads the class back to the main point of this call-up. This is then followed by a list of questions from the class members.

“Yeah, does anyone know the reason why Ritsu told us to be here?” Yada is the first one.

“I mean, it should be a serious matter that she called all the class members to be here, right?” Next is Mimura. 

“Wait, is there something bad happening to Itona?” Fuwa exclaims.

“Probably. I haven’t heard anything from him since 3 days ago. And look, he even put a ‘Closed’ sign in front of his store.” Yoshida says while pointing his finger at the sign.

“Well, maybe he’s just on a business trip with his father.” Kurahashi gives out her guess, hoping for the best scenario.

“But isn’t that his father hasn’t been with him for a while? Itona said his dad decided to open a new store in another city, leaving this one for him to manage. So, I don’t think that would be the case here.” Hazama explains.

“And even if he were on a long business trip, he would have told us about it.” Muramatsu refers ‘us’ to the old Terasaka group. 

“Ok, settle down everyone.” Karma says loudly to the group, trying to get their attention. “Instead of just randomly deducing and wasting time like that, why don’t we just ask the person who called us here?” Karma then takes out his phone. “Hey Ritsu, are you here?”

“Yes, I’m glad to see you guys are all here.” The purple-hair AI girl appears on Karma’s phone with a happy face and then changes into a sad face. “The thing is I need you guys to quickly burst into Itona’s store and find him. Something bad happened to him.”

Some of the class members have already anticipated this to be the case. They remain silent, waiting for an explanation from Ritsu. 

“What happened to Itona?” Terasaka asks with a loud voice.

“Please calm down. I know you all are worried and want to know what happened, but please, our first priority is to quickly find Itona and check his conditions. I’ll explain the details later.”

With that being said, all of them look at each other and nod in unison, being ready for what is waiting for them behind the steel door. ‘ _ Hang in there, Itona. We’ll get you out as soon as possible. _ ’

Without wasting any other second, all the male members gather in a horizontal line opposite to the large steel door and then strongly hit, kick, and push the door. After doing that for about 2 minutes, the door finally gets detached and collapses to the concrete floor.

“Why did Itona even have to use this secure door anyway?” All the guys say in a panting state.

Immediately, all the class members rush into the store to find Itona. They try to find him in every single room, but there is still no sight of the man. 

Manami gets her phone out and asks Ritsu. “Hey Ritsu, we couldn’t find Itona anywhere. Are you sure he’s still in here?”

Then Ritsu appears on the screen of everyone’s phone. “I’m sorry for not telling you guys this before. There is a secret room under Itona’s office. It’s hidden behind the bookshelves. You guys have to push it to the right and the path will be revealed. He’s in that room. Please hurry.”

Some of the members are surprised for a moment by the fact that Itona has a secret room, but then that thought is quickly replaced by the urge to find him.

After successfully finding out the secret path, they follow the long spiral stairs down and finally get themselves to the bottom. They are all awed by the sight in front of them.

“Guys, are you sure this is not an underground bunker because it looks like one to me?” Sugaya nervously asks.

“What kind of secret room is this anyway?” Maehara follows Sugaya’s question with his eyes widening.

“Unbelievable. Seriously, what does Itona use this place for?” Nakamura is also amazed by the view.

“Everyone, hurry. Itona is behind that door.” Ritsu says to the whole group.

Her words cause them to return back to the main objective. They quickly open the door in front of them and enter the room. What they see right now is Itona lying on the floor unconscious in his mechanical suit and mechanical tools just being all over the room.

“Itona!” All of them scream the name while running to the man.

“What happened here?” Okajima looks at Itona then turns to the room. 

“How long has he been like this?” Yukiko panickedly asks.

“He’s been like that since the moment I sent you guys the message. Please check if he’s still fine.” Ritsu answers.

Takebayashi kneels down and gives a quick check on Itona. “He’s still breathing. I guess he was hit by something from behind and got unconscious. There’s still a red line mark on the back of his neck. Though, just by observing, I’m not sure if he gets any side effects from the injury he took. Further analysis is definitely recommended.”

Some of them feel relieved when they hear that. At least they know for sure that Itona is still alive. 

Then Ritsu sadly makes an add-on. “It was a pretty strong hit, based on what I observed.” 

“So you said you were here the whole time? Then you must know who did this to him, right?” Karma quickly catches on with what Ritsu just said.

“…” Ritsu remains silent, not wanting to have them learn the sad truth.

“Answer me, Ritsu. Who did this to him?” Terasaka pushes the AI girl to talk.

The AI girl is very nervous to answer the question. “It…it was complicated.”

“Just tell us, Ritsu. Who?”

“It was Nagisa.” Ritsu answers with a very weak tone of voice. However, all of the other members still can hear her very clearly.

“Nagisa?!” All the girls in the class yell at the same time.

“What? That runt did this?” Terasaka surprisedly exclaims.

“Are you sure about that, Ritsu?” Still unsure about what he just heard, hoping that it was an error in Ritsu’s processing, Sugino nervously asks the AI girl once more to confirm it.

“Yes, I’m 100 percent sure. I was here, but I couldn’t do anything to help Itona.” 

The whole group is trying to process the information, the information that they believe it will never happen in millions of years.

Karma narrows his eyes at the lying man. ‘ _ Why did you do this, Nagisa? _ ’ He clenches his hands into fists at the thought. Then he quickly calms himself down and asks Ritsu for more information about Nagisa’s whereabouts. “Ritsu, do you know where Nagisa is now?” 

“I have an idea about that, but I’m not so sure…” Ritsu weakly responds.

This causes another commotion among the group. 

“Everyone, settle down. Let Ritsu say what she has first.” Isogai says to the whole group and then turns to look at Ritsu on his phone. “Ok, Ritsu, we really need to know what just happened here. We need the details now. ”

“So, the thing is Nagisa called me when he was already in Itona’s shop.” Ritsu slowly tells them what happened. “At that time, Itona was still fine. But then, Nagisa…he asked us to help him build a…a time machine…”

“Hold on! A what now?” Maehara stops Ritsu in the middle of her explanation, trying to make sure his ears are still working. 

“A time machine you said?” Fuwa asks with widening eyes. This gets a simple nod from Ritsu.

“Wait, is it even possible?” Takebayashi asks the digital girl.

“Yes, it is possible.”

“Really?” All of the class members exclaim at the same time.

Manami is the first one to notice something else besides the time machine. “Hey guys, I think we forgot the most important point here. Why did Nagisa need a time machine in the first place?”

This causes a ten-second silence among the group. 

“Oh no…” Sugino says with a worrying face.

“Is he insane or what?” Nakamura loudly asks.

“That stupid bastard. What did he think when he did all of this?” Terasaka yells.

“Ritsu, did you guys finish building the time machine?” Karma looks at his phone and asks.

“Yes.” Ritsu answers with her head hanging down.

“Did he use it?” Karma continues. Ritsu just gives him a nod. ‘ _ What the hell, Nagisa? _ ’ Karma thinks to himself after getting the answers from Ritsu.

“But then why did he even hit Itona like this?” Hara asks Ritsu. 

“That was because Itona tried to stop him using the time machine. Nagisa caught him off guard and hit him from behind.”

Disturbance once again comes back to the group. This time, Ritsu is the one to shut down all the noise.

“I know some of you are thinking about going to get him back, but I’m sorry. I will not allow you guys to follow him.” She says to the whole group. 

But at the same time, she is still trying to process each word Nagisa said to her during the last few minutes. ‘ _ Ritsu, you just don’t have any idea when someone whom you dearly love, someone who is destined to be with you until the end of life just dies in front of your eyes. _ ’ 

Of course, she wants Kaede to be alive. Everyone does. She is her friend, she is their friend. But looking deeply at it, that is all they have, just a normal friendship. It is not the case for Nagisa. And that, the AI girl wants to learn more about that feeling. 

“He’s very determined in doing what he believes is right.” 

**Notes for the Chapter:**

> Yes, a lot of Karma x Manami in this interlude. There are so many things with the future timeline, so why not using it to its full potentials? As you can see, I tried to include all the class members, but if I missed someone, please tell me. Also, I intended to explain the timeline issue in this chapter, but I think I should add it in the next interlude. For now, I want to post this sometime before Christmas. 
> 
> We'll be back with Shuwari Naoki in the next chapter. Interludes will be added after several chapters of Nagisa. Note that all the interludes will be about the future timeline.
> 
> Anyway, stay safe everyone! See you guys in the next chapter.
> 
> And MERRY CHRISTMAS!!!


	4. Introducing Time - Period 1

**Notes for the Chapter:**

> AN: Hello everyone. I'm back with a new chapter. Sorry if I took so long for this chapter. School already started, so I'm back with school works.
> 
> WARNING: This chapter does include thoughts of committing suicide, but not much. I just want to warn you guys first, that's all.
> 
> Anyway, hope you enjoy the chapter!

The sun rises, and another morning comes to a special school campus located on the top of a mountain. The sun warmingly shines on the campus while the birds are constantly showing off their beautiful singing voice around the campus. A small breeze of fresh air is giving off the coolness of a typical late-spring day in mid-May with the trees slightly dancing in sync with the flow. 

The old wooden campus that used to be gloomy and full of distress is now completely replaced by a lively one because of the arrival of a certain yellow tentacle creature to the campus. Since the coming of Koro-sensei, every morning, before the bell rang as the indication for the start of the first period, the Old Campus has become much more boisterous than ever before as most of the students have always been in their high-energy state to share their ideas on how to plan out the assassination for the day.

However, there is something different about today that causes the class to be a little bit less energetic than they usually were. 

“Hum…A new teacher…” Standing right next to Isogai’s desk, Maehara hums while rubbing his chin deep in thoughts. Then he turns to the large group gathering around the same desk. “So what do you guys think about this new teacher that Karasuma-sensei mentioned at the end of yesterday?”

“No idea.” Standing behind Isogai, Chiba calmly replies.

“Well, beat me to that.” Sugino, standing between Maehara and Chiba, answers while having his hands behind his head. 

“Yeah, how should we know? We have even yet met the teacher.” Leaning against his desk, Mimura exclaims.

“Ok, ok.” Maehara waves his hands. “Let me rephrase the question. Does anyone have any other information regarding the new teacher?”

“Karasuma-sensei didn’t tell us much about the situation. All he said is that there will be a new teacher coming today.” Standing opposite Isogai’s desk, Sugaya unwarily gives out his thoughts. “Well, at least based on how Karasuma-sensei referred to the new teacher, it’s going to be a he.”

Glaring at Sugaya, Maehara lets out a sigh. “You don’t have to restate the things that we’ve already known.”

“Hey, I’m trying my best to help here, ok?”

“But to be honest, that really tripped me up.” Okajima then speaks up in huge disappointment. “I was expecting to have another pair of huge boobs just like Bitc…” 

Suddenly, something flies and hits the back of his head. “Ouch. What the…?” Okajima turns around to see an angry Kataoka with red veins popping on her forehead.

“One more word from you and you’re done. Got it?” Kataoka fastly moves her hand that has already been clenched into a fist and stops right before hitting Okajima’s face.

“Y-yes, ma’am.”

“Hum…Maybe Okajima’s right.” Yada states. “The new guy can be another assassin sent by the government, just like Bitch-sensei.”

“I thought so too.” Maehara follows. “I mean, Koro-sensei is a state secret, right? Not many people know about his existence except the assassins getting hired by the governments. But it’s just that…”

“It’s just that you’re not so sure about it because there’s no evidence to back it up and that’s why you asked the others for more information?” Takebayashi continues Maehara’s words while using his finger to push his glasses up.

“Wow, your first line, Takebayashi.” Fuwa randomly comments.

All the other students standing nearby just blink nonstop at the girl with her nonsense talking. 

“But anyway, did you guys notice how frustrated Karasuma-sensei was when he told us about this? He wasn’t that frustrated when Bitch-sensei first came to our class though.” Standing near the teacher’s podium, Kurahashi raises her voice.

“Well, maybe the guy must have done something that just really pissed Karasuma-sensei off.” Standing opposite Maehara, Kimura adds while crossing his arms.

“That could be true. But we still can’t just deny the other possibility, which is that the guy isn’t an assassin hired by the government, right?” Kanzaki expresses her thoughts.

“It’s not that we’re denying it.” Hayami coldly says. “It’s just that the possibility of him being a hired assassin is much higher than the other one.”

“And if he’s really an assassin, I just hope that he won’t be stubborn and irritating like Bitch-sensei when she first came.” Kataoka follows. 

“Agree.” The whole group nods in unison. 

“Hehehe…” The sudden weird laugh causes the others to quickly turn to look at the source.

“I finally solved the mystery.” Fuwa continues. “A new mysterious male teacher who didn’t make a good impression on Karasuma-sensei is about to come and teach our class in which a high-order state secret is hidden. That only means one thing…” She starts smirking in front of the group.

All the others put all their attention on the girl, hoping this time that she may put herself with a much more serious effort.

“…Karasuma-sensei actually has a secret younger brother. Karasuma-sensei really loves him, so he didn’t want him to risk his life for this crazy mission. However, the younger brother determinedly went against Karasuma-sensei because he believed that it is his destiny to fight against the evil tentacle creature who one day will destroy the Earth. Therefore, he decides to disguise himself as our teacher, waiting for a perfect moment to make the kill.” Fuwa proudly puffs out her chest while still smirking. “Mystery solved.”

All the others are deadpanned, just facepalming and sighing hopelessly.

“Um, Fuwa-san, did you hit your head somewhere on the way to school?” Okano worriedly asks the girl.

“Seriously, you’ve been reading too much manga, Fuwa-san.” Hara comments, showing her complete disappointment at her friend.

“What? You guys don’t believe it? Just for you know, my explanation is always flawless.”

“No, no, no. Your story has too many holes, Fuwa-san.”

“Come on. My plot is very logical. You guys just need some time to fully comprehend it.”

“Um guys…” Isogai, who has been silent during the whole discussion, gently says to the group. “…I know that we’re all curious and want to learn more about this, but you guys don’t have to surround my desk like this, right?” 

However, the others just ignore his words and continue on with their discussion.

“Hey, why don’t we go to the teacher lounge and eavesdrop on the situation? Maybe he’s already there by now.” Maehara suggests.

“No, no, no. I don’t think it’s a good idea. It’s almost time for the homeroom period.” Kataoka explains. “Koro-sensei will be in class soon. Do you want to be in class on time or do you want to have your homework to be tripled?”

“Also, with not much time left until the first period, we’re not going to get any much information anyway.” Sugino continues the explanation.

“Then we can only wait?”

“I guess so.”

“Come on…”

Standing outside of the talk, Nagisa just smiles sheepishly while carefully observing the class. ‘ _ Well, I can understand why all of us are so eager to know more about this new teacher. We only have a little more than a week left till the first midterm exam. And giving the fact that we know nothing about the guy, we’re expecting for the worst in which the new teacher, whether he’s an assassin or not, won’t care much about our education because we’re in class 3E after all. _ ’

Nagisa still ponders while slowly changing his gaze from the large group to the back of the classroom. ‘ _ I hope for the least that he’s a reasonable guy and has some respect for us. _ ’ Then he notices that Karma, sitting at his desk, is just calmly smiling. ‘ _ Hum… _ ’ With curiosity growing inside, he walks toward the red-hair. 

“So what are your thoughts about this, Karma-kun?”

“If you’re talking about the new teacher, I have to say, it depends.” Karma shrugs while leaning his back against his chair, having his hands in his pockets and also pondering about something. ‘ _ Maybe I can give this new guy a chance to see how good a teacher he can be. _ ’ 

Then, Karma turns to look at the one who is irritatingly sitting on his right. “Well, well, well. Why don’t we ask our tough guy over here? He’s been unusually silent this morning. So, what do you think, Terasaka?” He asks with a smirking face.

“Tsk. Like I care about all of those things.” Terasaka answers while getting annoyed, eyes twitching, by Karma’s face.

“Oh, is that so?” Karma says with a mocking voice. “But your idiot face obviously tells me otherwise, tough boy.”

Terasaka angrily slams his desk and then points his finger at the red-hair. “You better watch your mouth, Karma.”

In response, Karma just lets his tongue out while giving another mocking look at Terasaka.

“Why you…” 

When Terasaka is about to jump out of his seat, both Yoshida and Muramatsu immediately try to cool down the angry boy. “Hey, hey. Calm down, man. It’s just a joke.”

“If you guys don’t shut up, I won’t hesitate to put a curse on you guys to seal all your noisy mouths.” Hazama coldly says while still having her eyes gluing to her book. 

Nagisa nervously scratches the back of his head while observing the sudden outburst. ‘ _ Well, that didn’t go as well as I expected. _ ’

Then he turns around to notice the purple-hair girl, who has been sitting quietly at her desk, being a little bit more anxious than usual.

“So, how about you, Okuda-san? What do you think about the new teacher coming today?”

“U-Um, I-I don’t know.” Okuda answers while having her head down.

“O-kayyy…” Nagisa just sweatdrops at her too brief response. ‘ _ Well, that was a typical Okuda for you. I shouldn’t have expected much from her answer. _ ’ 

“Hey, don't be so stiff, Okuda.” Nagisa quickly turns himself to the source of the voice. Kayano approaches the girl with a smile and puts her hand on Okuda’s shoulder. “Just relax, alright? We’re all in this together.”

Okuda lifts her head up and gently smiles back. “Thanks, Kayano.” 

“Do you have any thoughts about this, Kayano?” Nagisa asks.

“Well, I’m not sure but I have a feeling that I’ll prefer Koro-sensei to be the one teaching us.” Kayano sheepishly answers. But deep inside her, she is really annoyed by another sudden addition to the class. ‘ _ I don’t give a damn about this new guy or whatever he’s going to do as long as he’s not going to mess up my plan of killing that murderer. If he’s in my way, I’ll make sure he pays for it. _ ’

\------------------------------

***Two hours earlier***

Right at the base of the mountain, Nagisa, dressing up as Naoki, breathes heavily and anxiously looks up while trying his best to stand on his shaking legs. ‘ _ Come on, come on. I can do it. _ ’ He says to himself while struggling to move forward. ‘ _ This is just the start. How can I save her if I can’t even get over this? _ ’

With all the energy that he has, he tries to lift his legs one at a time. ‘ _ That’s right. I can do it. _ ’ With each step he makes, his breath becomes heavier. ‘ _ Just don’t think about anything and keep moving forward. _ ’

However, after a few minutes, his vision starts getting blurred, and he barely moves. ‘ _ What’s going on with me? _ ’

It is like he suddenly becomes blind that he has to use his free hand to randomly swing in front of him. Memory and reality start flashing back and forth right before his eyes. ‘ _ No, please. Don’t do this to me. _ ’

_ “It’s been a while since the last time we were here together.” Kaede said while happily ambling, climbing up each step forward, and enjoying the surrounding view. “Ahhhh, nothing much has changed. The fresh air, the trees. Feel so good. Hum, the path does look a little bit smoother and newer than before. Well, they did tell us that they have been working on these. But it makes me feel really bad for not being able to help them at all. My schedule is so packed right now that I barely have time to go out with you, and you’re also busy with your teaching job too. Maybe I think we should make some adjustments to our working schedule. I’ll contact my manager later to have a talk about that. What do you think?”  _

_ Kaede turned around to look at the one who had been behind her since they started climbing the mountain, waiting for his answer. “Nagisa?” _

_ Contradictory to the happy Kaede, Nagisa, barely moving at all, was thinking about something that he did not even notice his surroundings. ‘Ok, ok. I really need to calm down right now. I’ve been too nervous since we were in the car. I can’t mess this up. Wait, did I bring the thing?’  _

_ Then he quickly moved his hand to his pocket to check if it was actually in there. In fact, this was the tenth time he did that. ‘Ok. I have the thing. Now, just relax, review what I’m going to say, be confident, and then I’m all set. Just that simple, right?’ _

_ “Nagisa?” Not getting any answer from him, Kaede sighed and slowly moved back to his spot.  _

_ ‘Nope, I’m not ready at all. Damn it. The stress just keeps building up.’ _

_ “NAGISA!!!” This time, Kaede yelled right in front of his face. _

_ “YES, YES.” Nagisa responded loudly. Then he quickly noticed his girlfriend was standing with her arms akimbo and frowning at him. “Ah, Kaede. Sorry, what happened?” _

_ “What’s wrong with you today? You haven’t said a single word since we first arrived here. You didn’t even listen to what I just said a minute ago.” She crossed her arms while still frowning at him. _

_ “Ehhh…Nothing…It’s just that I was just thinking about something, not really important. Sorry if I was acting a little weird. Anyway, what did I miss?” Nagisa asked while worriedly scratching the back of his head. _

_ “Now, I’m curious. Can you tell me what you were pondering about, Na-gi-sa?” _

_ “Ok, now it’s you who are acting weird all of a sudden.” _

_ “Well, I’ll be like this for the rest of the day if you don’t tell me what’s in your mind, Na-gi-sa.” _

_ “Ok, ok. Just stop doing that, Kaede. I’ll tell you but not right now.” _

_ “Huh? Why not now?” _

_ “I have my own reason for that. You’ll see.” _

_ “No, I want you to tell me now.” Suddenly, Kaede started whining. “Or is it that you were thinking about another girl? Is that why you don’t want to tell me? You don’t love me anymore?” She had her face covered with her hands while sobbing. _

_ “What? No, no.” Nagisa nervously waved his hands. “Kaede, you know that you are the only girl that I love, right?” Not knowing what would be the best, he decided to gently hug her. “Come on, please don’t cry. I’ve never had a single thought about any girls except you. You’re the only girl in my mind. I love you, ok?” _

_ Having her face on his chest, she started giggling. _

_ “Kaede?” _

_ Then she moved back from him and burst out laughing. “Hahaha…That was the twentieth time I got you, Nagisa. I can’t believe you still fell for that.” _

_ Nagisa just hopelessly sighed at his carefree girlfriend. “Really? Why do you keep doing that to me?” _

_ “Because it’s always fun to see you like that. And also, I never get tired of hearing you saying that…” _

_ “The ‘I love you’ one?” _

_ “Yeah.” Kaede happily nodded. _

_ “If you want, I can keep saying it nonstop, but I’m afraid you may start getting annoyed before I even feel tired.” _

_ “Is this a challenge for me?” Kaede raised one of her eyebrows while smiling at him.  _

_ “If that’s how you see it, then yeah.” _

_ “Ok, what do I get if I win?”  _

_ “If you win, I’ll do whatever you want. If you lose, nothing will happen. Good?” _

_ “Alright then, I accept the challenge.” Kaede smirked. “I’m pretty sure I’ll be the one to win this, Nagisa.” _

_ “I think you underestimate me too much, Kaede.” _

_ “Let’s see about that. But as eager as I want to settle it at this very moment, we have to leave it aside for now. We need to hurry up.” _

_ She replaced her smirk with a warming smile and reached out for his hand. “Come on, Nagisa. They’re waiting for us.” _

“Akari…” Nagisa mutters to himself while still randomly swinging his hand, hoping that he can reach out for her hand once again.

However, the moment he makes his next step, he trips over and falls to the ground. “Why…” Tears come out of his eyes. “Please make this stop.”

_ “Hi sis. Hi Koro-sensei. I’m sorry for not being here with you guys as often as before. I’ve been too busy with my acting career. Again, sorry if you two felt a little bit lonely.” Standing in front of the side of the building, Kaede said with her hands clasping together. “But if you worry about me overworking, please, you just waste your energy. He always keeps me in check. You know how he was when we were here together last year, right?” _

_ “You don’t have to say things like that, Kaede.” Nagisa turned around to look at her, raising one of his eyebrows. “I was extremely worried about your health. You almost fainted the last time we were here.” _

_ “It wasn’t that bad though. I could handle myself, you know.” _

_ “No, no, no. You can do whatever you like, anything except this. You just focused on your work too much and paid no attention to your being at all.” _

_ “But that doesn’t mean you have to monitor my health daily.” _

_ “Ok, do you want me to tell your sister and Koro-sensei all the time that you lied to me that you were feeling fine and then suddenly fell unconscious a few seconds later? I have the whole list ready in my mind.” _

_ “Urgh, fine. You win this time.” Kaede puffed her cheeks. “Why do you always get to be the dominance whenever we have a talk about this?” _

_ “Because it’s my duty to keep my girlfriend’s health at top-notch.” _

_ “Ok, ok. It was my fault. But enough with that, I really want to know what you said to them, Nagisa. I didn’t hear anything from you.” _

_ “It’s a secret.” _

_ “Again? You’re acting very suspicious today, I tell you that.” She frowned while crossing her arms. “Anyway, where are the others? It’s been about 20 minutes since we got here and we still haven’t seen anyone.” She said while looking around the campus.  _

_ “I don’t think they’re going to come.” Nagisa murmured as he looked at the direction of the climbing path.  _

_ “Come again?” _

_ “I said that they’re not going to be here.” _

_ “But why? Isogai did message us and the others to come here for something special, right?”  _

_ “Well, I was the one to ask him to do that.” He said while nervously scratching the back of his head.  _

_ “Huh? I’m not sure that I’m following what you said there.” Kaede looked at him with a very confusing face. _

_ Turning back to her, he asked. “Can I ask you something, Kaede?” Nagisa’s cheeks got a little pink. “It’s a very important thing that may change both our lives from now on.” _

_ “Su-re…” _

_ Without saying anything, he kneeled on one knee. _

_ “What’re you doing, Nagisa? Why are you sud…”  _

_ Not paying any attention to Kaede’s words, he took out a small box from his pocket and opened it, revealing a simple but beautiful ring with a small diamond attached to it. _

_ Realizing his true intention, Kaede’s eyes widened in shock, tears almost coming out of her eyes. She had her hands over her mouth. “Nagisa…” _

_ After regaining his composure, he gave her a determined look, the look that she came to love. Taking a deep breath, he started saying. “Kaede, I’m very pleased to be with you as your boyfriend for the past two years. Ever since the first time we met at this place, you’ve always been here for me. You’ve been supporting me, giving me the confidence that I need. And day by day, I started to realize that my life won’t ever be complete if I don’t have you with me.” _

_ “I know that I may not have a great outlook like some of the actors that you’re working with. I may not have the capability to buy you a luxurious house or a mansion. My job sometimes may not allow me to have much time being with you. And again, I’m sorry for making you wait six years only for me to realize your feelings. I was a dense idiot.” _

_ “But allow me to use the rest of my life to make up for those things. I’m willing to spend every second of the rest of my life being with you. I’ll give my best to make you the happiest woman in the world. So, Yukimura Akari, will you marry me and let us be together side by side until the end of time?” _

_ Standing in front of him, she could feel tears coming out of her eyes. “Nagisa…” _

_ He worriedly looked at her. “Akari, did I…” _

_ However, his words were cut off by her nod and weak voice. “Yes, I want to marry you and be with you until the end of time, Nagisa.” _

_ Nagisa started blushing and happily smiling. Then he gradually stood up. “Can I put this on your finger?”  _

_ She nodded and moved her left hand to him. Nagisa gently held her hand and put the ring on her ring finger. “Thanks, Akari.” He then hugged her and kissed on her lips. She also happily returned the kiss.  _

_ After they broke the kiss, she laid her head on his firm shoulder while still hugging him. “Let’s spend the rest of our time together, Nagisa.” _

_ Nagisa affectionately smiled at her. “Yes, Akari.” Then he looked back at the building. ‘Yukimura-sensei, Koro-sensei, please be our witnesses. I promise that I’ll protect her with my own life.’ _

“No, I can’t take it anymore.” Nagisa screams while tears keep running on his cheeks. “Why am I so useless? Why am I still alive?” 

**_“Stop ill-treating yourself, Nagisa. You already did your best.”_ **

A warming voice causes him to look up to see a familiar silhouette with long curly hair in a white dress standing in front of him. “Akari…Is that you, Akari?” 

The silhouette starts to reveal her face, a gorgeous face with amber-pupil eyes, and gives him a warming smile.  **_“Come on, Nagisa. Everyone is waiting for you.”_ **

“No, Akari. No one is waiting for me anymore…No one…” Nagisa miserably looks down at the ground.

**_“You’re wrong, Nagisa. They are always there for you. You just need to open your heart to everyone again.”_ **

“But you’re not here for me, Akari. You’re not here…You left me…You left me alone. TELL ME, Akari.” Nagisa screams in despair. “Why did you not let me go with you? Why did you make me suffer like this? I failed my promise. I failed you. I should’ve been the one to die, not you and Naoki.”

**_“You idiot. We’re always here with you.”_** The silhouette points her finger at his chest, right at his heart.

“Akari…” He turns back to look at the silhouette. “…you’re going to stay with me, right?”

**_“I’m sorry, Nagisa.”_** The silhouette faintly smiles while gently shaking her head. **_“As long as I want to be with you physically, I’m after all just an afterimage created by your memory. I can’t stay with you forever.”_**

“No, it’s not true.” He shakes his head in denial. “Oh, I know. You were just putting a prank on me again, right?”

**_“You’re just torturing yourself, Nagisa. You still can’t accept the reality, that’s what’s happening. You really have to let the past go away.”_ ** The silhouette starts to fade away. 

“No, Akari…Please stay with me.” Nagisa tries to reach for her hand but fails.

**_“I know that you can. I believe in you, Nagisa.”_ ** The silhouette completely disappears right in front of his eyes.

“Noooo…” 

‘ _ Can’t take this anymore…Have to do something… _ ’ He then decides to bite his tongue, a little off from the main bloodstream so that there is only a little amount of blood coming out. The pain causes him to go back to reality. 

He quickly takes a deep breath to calm himself down. “It’s just getting worse day by day. It’s only been more than a week, but I can feel like I’m not myself anymore. I don’t even know if I can keep my mind straight up till the time I finish the job when this is still just the beginning.”

He clenches his hands into fists while grinning his teeth. “No, I have to keep this up. This is for Akari…This is for Akari…This is for Akari…” He keeps saying to himself while continuing his way to the top of the mountain.

When he arrives at the top, standing far away while observing the building, a solitary tear runs on his cheek as he recalls back when he proposed to her right at this place. He firmly holds the ring on his necklace. “I promise I’ll make it right this time.”

After stepping into the building, he moves toward the teacher lounge. But then he suddenly stops right at the classroom door. He decides to take a quick peek at the inside. He believes there should be no one on the campus right now since it is still quite early in the morning. Gently opening the door without making any noise, he quickly looks around and faintly smiles at the usual emptiness of the room. “After many years…”

He closes the door and gets to the teacher lounge. Right after he opens the teacher lounge’s door, a loud pop noise gets into his ears. 

“What the…” A large amount of colorful confetti is falling down to the floor. A large sign “Welcome to 3E” is hung across the room.

Suddenly, a certain yellow octopus in a cheerleader costume jumps out of nowhere and makes 3 clones around Naoki. “Welcome to 3E. Welcome to 3E. Welcome to 3E.” 

Nagisa just facepalms but still slightly smiles at the sight. ‘ _ Glad to see you again, Koro-sensei. _ ’ 

“Can you please stand still for a moment?”

“Nurufufufu.” Koro-sensei stops and makes his stand in front of Naoki, already in his usual teacher uniform. “I suppose you’re the new teacher. Karasuma-sensei told me about your coming, so I wanted to make a little welcome party. Hope you like it.”

“Well, I do appreciate your efforts.” Naoki smiles. Then he pretends to carefully observe the 3-meter-tall figure, acting like this is the first time he saw Koro-sensei. “But I guess the rumor is true after all. You’re really an octopus.”

Koro-senses puts on a purple X face. “Please don’t call me that.” Then he changes back to the normal one. “I have a name. Koro-sensei if you will. It’s a precious name that the students gave to me.”

“Nice to meet you, Koro-sensei. My name is Shuwari Naoki, but please call me Naoki.” 

“It’s a pleasure to meet you too, Naoki-sensei.” Then Koro-sensei simultaneously moves around Naoki to have a closer look at the guy. “But I have to say, I’m in big surprise that you’re still acting cool and not being afraid of me at all.”

“What do I say?” Naoki shrugs. “I must have gone through things that are much more terrifying than you.”

“Well, it does hurt my pride to know there’s someone that thinks so little about me though. But I think this will be much better than if you were afraid of me. At least it’ll make the teaching environment not too awkward for everyone here.”

“I really do look forward to learning more about this unusual environment around here this school year.”

“Glad to hear that.” Koro-sensei stops moving and then weirdly rubs his imaging chin with his tentacle. “But can I ask why you are so…so dusty right now?”

“To be honest, I accidentally fell down on the way here. The path is a little rougher than I expected. Well, it is my first time being here after all.”

“If that’s the case, allow me to fix it for you. You can’t let the students see you like this. Too messy…”

“What do you mean by…” Before Naoki even has a chance to finish his words, Koro-sensei has already started once again simultaneously moving around him. But this time, he can feel Koro-sensei’s tentacles are touching his clothes everywhere.

“Hey, what’re you…”

Within a moment, Koro-sensei has already finished with whatever he was doing. “Nurufufufu. Clean as new.”

Naoki looks down at himself to realize that his shirt and pants are amazingly clean without any trace of dirt. “Thanks, I guess.” 

Naoki then looks back at Koro-sensei and sighs. “But please don’t do things like this ever again. Just don’t cross my personal boundary, ok? I have my own privacy.” 

‘ _ I need to keep him at a distance from me, or else I’m going to be on his list. _ ’

“Sure. Sorry if I made you feel uncomfortable.”

“Ok, but just this one time.”

“If that’s what you insist. But before we jump into discussing the teaching plan, can I ask you one more thing? It’s been bothering me since the moment you were here.”

“Sure, go ahead.”

“Did I meet you somewhere else before by any chance?” 

“And what makes you say that?” Naoki annoyingly frowns at Koro-sensei.

“Believe it or not, I have a pretty good nose. I can easily distinguish everyone’s smell from the first time, at worst the second time I meet the person.”

“Is that so?” Naoki raises his eyebrows, pretending to be amazed by his ability. ‘ _ This is exactly why I want him not to be too close to me. And I thought I already used a very fair amount of dense perfume, but it seems that it didn’t do the job as well as I expected. _ ’ 

Then he shakes his head. “But I don’t think we’ve ever met before. I would remember deeply in my mind if we met each other because you look too, you know, anomalous. Sorry if that offends you.”

“No, you’re good. I’m already used to that. But I guess I have to go and fix my nose after this.” Koro-sensei says while instantly taking a piece of paper out of nowhere and writing something down. 

After finishing his note, Koro-sensei turns back to Naoki. “Anyway, let me briefly explain how things work on this campus. Right now, Karasuma-sensei is responsible for the PE class and I assume you already knew that. Another teacher, which you’ll meet later, teaches English communication. She’s very good at a fair amount of other foreign languages too.” 

Koro-sensei quickly comes near Naoki and whispers. “She’s also an assassin. And a little secret between us, it’s always refreshing for me to look at her big you-will-see.” He says with a slithering voice and his pink face.

Naoki just sweatdrops when he hears that. ‘ _ Koro-sensei, seriously? _ ’

Then Koro-sensei moves back and continues. “Ahem. And lastly, I’ve been handling all the other subjects until now. Sometimes you may see the students will try to kill me with their assassination plans, but please just ignore that. Karasuma-sensei did mention that you’re not an assassin, but you’re also welcome to try and kill me if you find it interesting. Guns and knives specifically made for killing me are everywhere around this campus. Anyhow, Naoki-sensei, what subject do you want to teach?”

“Thanks for your offer, but no thanks. And to answer your question, I think I want to teach Math this time even though English is my specialty. Sounds good for you?”

“Of course. If it’s good for you, then it’s good for me. So we’re fellow colleagues, right?” Koro-sensei moves one of his tentacles outward, waiting for a handshake.

Naoki looks at the tentacles for a moment and then decides not to take the shake. ‘ _ No, I can’t risk doing that. For now, I can’t leave too many traces of mine on him. _ ’

“Sure.” He says while standing still, not moving any of his hands to answer the shake. 

Suddenly, the lounge’s door opens, revealing a spike-hair man in a black suit. “What is the deal with all the mess in here? Can you two please explain this?” Karasuma’s eyes twitch. 

Naoki turns back to wave at Karasuma. “Good morning, Karasuma-sensei. You see, Koro-sensei here made a little welcome party for me.”

“Ehhhhhhhh…Naoki-sensei, please don’t throw me under the bus like that.” Koro-sensei nervously waves his tentacles at the two.

“Why you…Did I tell you not to overdo things?” Karasuma sighs and annoyingly asks while pinching the bridge of his nose.

“Well, I don’t think I heard it at all. Also, this is how socializing works, right?”

“I don’t want to hear any excuses from you. Just quickly clean this mess up right now.” Closing the door, Karasuma says and then moves to his working desk. 

“You just don’t know how to socialize, that is.” Koro-sensei quietly mutters to himself. 

“What did you say?” Karasuma glares at Koro-sensei.

“Um nothing.” Sweats drop like rain on Koro-sensei’s face while nervously whispering. “Let me clean the mess up really quick.”

Naoki just slightly shakes his head in disappointment. ‘ _ So this is what Karasuma-sensei had to deal with every day. _ ’ 

“And Naoki-sensei, what’re you standing there for? Your desk is right here.” Karasuma-sensei says while pointing at the unused desk next to him.

“Thanks.”

**Notes for the Chapter:**

> AN: Again, as I mentioned, school already started, so it'll take a much longer time to upload a new chapter. This is applied to both of my stories if you read both of them.
> 
> Again, I'm open to any comments, questions.
> 
> As usual, stay safe everyone! See you in the next chapter.


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